1. Technical Field
The present invention relates to a method of preparing alloy particles used as a catalyst for fuel cells, and more particularly, to a method of preparing nano-scale alloy catalyst particles by a simple single process.
2. Description of the Related Art
Until recently, despite several decades of research into fuel cells, it has been difficult to commercialize fuel cells. The main reasons for this difficulty are high cost for a platinum catalyst used as an electrode for fuel cells and deterioration in durability of the catalyst due to corrosion and detachment of the catalyst in the course of cell reactions. In order to resolve these problems, research into improving performance and durability of catalysts for fuel cells have been carried out in various ways. Namely, various studies have been made to attach a specific functional group (nitrogen and the like) to a carbon support for a platinum catalyst, to form an alloy of platinum particles with other metals, and the like. However, no satisfactory results have been provided yet in the art.
Currently, platinum has proven to exhibit the best performance as an electrode catalyst for fuel cells. Based on the platinum catalyst, many studies are focused on addition of various secondary metals to the platinum catalyst. Namely, in order to decrease poisoning of catalysts due to minor amounts of carbon monoxide (CO) residing in a fuel for an anode (anode), studies have been made to add ruthenium (Ru), tin (Sn), molybdenum (Mo) and the like to the platinum catalyst. In a cathode, oxygen reduction reaction (ORR) occurs very slowly as compared with hydrogen oxidation reaction, which is a main cause of decrease in fuel cell performance.
Therefore, in order to increase the rate of ORR, various studies have been made to develop alloy catalysts, such as Pt—Co, Pt—Cu, Pt—Co—Cu, Pt—Pd, and the like, which are formed by combining the platinum catalyst with cobalt (Co), copper (Co) or palladium (Pd) and the like. Further, there has been a study for synthesizing such metals in a core-shell structure.
However, according to the results of these studies, various metals must be sequentially supported and intermediate treatment must be included in each procedure (Korean Registered Patent No. 10-823502). For example, when a catalyst is prepared by an incipient-wetness impregnation method, the method includes drying, firing, and the like. When a catalyst is prepared by a template method, the method includes separately manufacturing a template, strong-acidic treatment to dissolve the template, and the like, which are complicated and hazardous processes.
[Patent Document] Korean Patent No. 10-823502